This invention relates in general to the field of telephony communications, and more particularly to supporting multiple telephony communications through a single network.
Rapid advances in technology relating to telephony communications have led to increasingly useful applications for both businesses and homes. The Internet and World Wide Web now reach millions of businesses and homes around the world in what is commonly coined the xe2x80x9cInformation Super Highway.xe2x80x9d
One driving force behind the Information Super Highway has been the development and reliance upon uniform data transmission protocols such as the transport control protocol/internet protocol, known as TCP/IP. This protocol and other common protocols, such as hypertext transport protocol, have made the internet and World Wide Web accessible to virtually every computer.
One recent useful internet application relates to the transmission of voice, video, or other communication data through a personal computer and the Internet using a TCP/IP digital data stream. Using voice as an example of one type of communication data that can be transported in a digital data stream will help to make clear the economic potential of this technology. A personal computer user can speak into a microphone associated with his computer. The computer accepts the electronic signal from the microphone and converts the signal into digital data. The digital data can then be injected into a TCP/IP digital data stream and directed to another computer interface with the Internet anywhere in the world. Thus, the two users can communicate as if by telephone but without placing a direct call to each other.
The ability to inject voice and other communication data into a TCP/IP or other digital data stream has many attractive advantages to computer users. For instance, two internet computer users can communicate with voice, video or other data through the Internet without incurring any long distance telephone fees. Each user simply must have a local internet connection, such as through an Internet service provider, and each user must know how to contact the other user such as with the other user""s internet address.
One difficulty with communicating voice data over the internet is that each user must have a personal computer loaded with software capable of accepting the digital telephony data and converting the digital data into normal sounds. Users must be xe2x80x9ccomputer smartxe2x80x9d to accomplish such communication, and each user must invest in hardware and software adequate to handle the demands of converting the digital data stream to voice or other communication data, and vice versa.
Another difficulty of present technology for transmitting voice and other communication data through the internet is that a computer interfaced with the internet typically ties up the telephone line used for that interface. For instance, an internet user interfaced through a residential phone line can make unusable all other telephony devices associated with that residence""s telephony network. Thus, each connection to the internet requires a separate telephone line or other transmission medium. This can result in significant wasted band width since the telephone line is tied up by the internet interface, even if little or any actual data is transmitted across the internet at any given time.
An internet user can increase access to the internet in a number of ways. First, the internet user can have second or multiple telephone lines run to his house or business. However, each telephone line carries an additional cost. Alternatively, an internet user can have high band width lines, such as ISDN or other dedicated services, interface with his home to allow greater amounts of data through the internet to the user""s computer. Again however, such lines carry additional expense and result in wasted bandwidth during periods of reduced need to transmit data over the internet.
Therefore, a need has arisen for a method and system which supports transmission of telephony data through the internet with minimal hardware and software costs.
A further need exists for a system and method which uses existing telephone systems to transmit digital data in a way that fully utilizes available bandwidth.
A further need exists for a method and system which simultaneously supports internet access, communications data transmission, such as voice and video data, and existing telephony communications without interfering with each other.
A further need exists for a method and system that promotes transmission of communications data, including telephony data and control data, but that remains downward compatible with existing telecommunications equipment, including installed residential and business telephony networks that utilize single twisted pair telephone lines.
A further need exists for a method and system that supports internet connections without blocking the acceptance of additional telephony communications to a telephony network.
In accordance with the present invention, a method and system for interfacing a telephony network and a digital data stream having communications data is provided that substantially eliminates or reduces disadvantages and problems associated with previously developed methods and systems for transmitting digital data over a transmission medium. A digital data stream having at least one telephony data set is transmitted through a transmission medium at a transmission medium band to a telephony network. The telephony data set is converted to a telephony signal and transmitted through the telephony network in a telephony network band.
A user can generate an outbound telephony signal with the telephony device for transmission across the telephony network in the telephony network band. The outbound telephony signal can then be converted to an outbound telephony data set for transmission through the transmission medium in the transmission medium band.
More specifically, the present invention allows for the conversion of an existing telephony network, such as the single twisted pair typically found in a residence, into an equivalent multi-line, multi-station telephone system. Telephony networks can be supported with existing twisted pair lines or other lines, such as untwisted pair lines, coaxial cable, and fiber lines whether shielded or unshielded lines, and wireless networks. The telephony network has plural telephony nodes, such as the tip and ring interfaces and RJ-11 jacks common to the industry and that allow telephony devices, such as telephones, to interface with the single twisted pair. The telephony network can receive a digital data stream through at least one of the telephony nodes or through another interface operable to receive a digital data stream from a transmission medium. For instance, a home can receive a TCP/IP internet data stream from an internet service provider through a telephone line interfaced with a central office, the internet data stream including the digital data in the voiceband of the telephone network. Alternatively, a home can receive an internet data stream through a broadband service, such as a coaxial cable and a cable modem, and can make the digital data stream available to the telephone line through an interface with a computer system. The digital data stream can contain communications data, including telephony data for supporting telephony communications, and control data for supporting functional operations such as environmental, security, meter reading, and power control. The digital data stream can have plural telephony data sets, each set supporting telephony communications, such as voice communication, video communication, or fax communication.
A digital converter associated with the telephony network can convert each telephony data set into a telephony signal, such as an analog voice signal typically used to support telephone voice communications. Each telephony signal can be transmitted over the telephony network in a telephony network band by translating each telephony signal to an appropriate telephony network band frequency with frequency translators, such as frequency modulators. For instance, a control program can use frequency division multiplexing to transmit two-way telephony signals, such as will support a telephone conversation, in a first and second channel within a telephony network band. The control program can direct the transmissions to occur outside of the central office voice band to prevent interference with central office signals. Further, control program can support plural telephony and other functions in plural telephony network band channels by ensuring that transmission channels have adequate separation to avoid interference.
Telephone control modules interfaced with the telephony network can receive the telephony signals in the telephony network band and can translate those signals, such as with a frequency demodulator, to a band appropriate for a telephony device, such as to the voice band used by most telephone devices.
A processor and control program can communicate with the telephone control modules to arrange transmission of each telephony data set to predetermined telephone control modules. For instance, if a telephony data set includes identification data associated with a predetermined telephone control module, the processor and control program can direct the converter to convert the telephony data set into a telephony signal for transmission through a telephony network band. The processor and control program can then direct the telephone control module identified by the telephony data set to receive the telephony signal at the predetermined telephony network band. A frequency translator associated with the telephone control module can then translate the telephony signal to the voice band for use by a telephony device.
In one embodiment, the method and system of the present invention can support multiple telephony communications with multiple telephony devices simultaneously over a single twisted pair line. The digital converter can accept the digital data stream, and can convert plural telephony data sets within the digital data stream into plural telephony signals. Each signal can then be transmitted across the telephony network at that signal""s own telephony network band, or so that each signal is transmitted at its own channel within the telephony network band. The processor and control program can communicate with the telephone control modules so that only predetermined control modules will receive telephony signals transmitted at predetermined telephony network bands or channels. Thus, as one example, two telephones interfaced with the same twisted pair can simultaneously communicate in separate conversations transmitted as telephony signals at different telephony network bands.
In alternative embodiments, the present invention can use techniques in addition to or as a replacement of frequency division multiplexing in order to support multiple telephony signals on an existing telephony network, such as a single twisted pair. For instance, the converters can combine the use of frequency division multiplexing with time division multiplexing or packet-based signaling, such as STM or ATM, to transmit telephony signals over the telephony network in the telephony network band as digital data. The telephone control modules can then translate the telephony signals to analog signals in the voice band for use by a telephony device. The telephone network band can exclude the central office voiceband to avoid interference with central office signals; alternatively, the telephone network band can include the voice band with low power transmission techniques such as spread spectrum transmissions.
In alternative embodiments, the present invention can cooperate with available telephony functions of the central office to enhance communications available to the telephony network. For instance, if a telephone line associated with a telephone number is in use, a call directed to that telephone line can be call forwarded as an available service of most central offices. The call can be forwarded to a voice gateway for conversion to a TCP/IP digital data stream and for transmission over the internet by an internet service provider. The internet service provider can direct the digital data stream to an internet connection of the telephony network so that the forwarded call can be placed to the intended recipient. Thus, for instance, if a user is interfaced with the internet through the user""s telephone line, the user can receive telephone calls placed to him. The control program can make the method for receiving the telephone call through the internet indiscernible to the user by making the call available to the user""s standard telephone network and telephone as if the telephony network were not being used to interface with the internet.
The present invention provides important technical advantages. For instance, a home or business having a single twisted pair line can support plural telephony communications simultaneously. The additional telephony communications are supported with minimal hardware and software enhancements and without the need for rewiring the home or business.
Another important technical advantage results from the ability of the present method and system to accept a digital data stream from any transmission medium for conversion to a form usable by analog telephony devices commonly found in homes and businesses. Thus, the present method and system can allow the use of advanced technology but also supports existing telephony equipment in a user friendly manner.
Another technical advantage of the present invention is the ability to use communication data simultaneously, including telephony data and control data. Thus, for instance, the present method and system can support telephony communications, such as a telephone call, while simultaneously supporting communication of control data, such as environmental, security, meter reading or power control data.
Another technical advantage of the present method and system is the ability to accept and use a wide variety of digital telephony data. For instance, the data stream can include video, voice, fax, e-mail, or other forms of digital communication across any transmission medium at any transmission medium band. The present method and system can reserve the voice band on the telephony network to avoid interference with central office telephony communications, and use other frequency bands to maximize the amount of data that can be transmitted over a given network wiring system.